Nowadays, many mobile phones or smartphones are provided with at least two camera modules. One camera module frequently comprises exactly one optical channel for detecting a partial area of the object area. A primary camera that can be optimized for capturing photos or video is, for example, on the front side or second main side of the apparatus facing away from the user and a secondary camera that can be optimized, for example, for video telephony, is provided on the rear side or first main side of the apparatus facing the user. Thus, two object areas independent of one another can be detected: a first object area facing the front side of the housing as well as a second object area facing the rear side. For illustration purposes, FIG. 11 shows a conventional camera and two camera modules (indicated by a circle, secondary camera (video telephony) on the left, primary camera (photo camera) on the right), respectively, in a smartphone according to conventional technology.
In the course of increasing miniaturization, one of the main design objects is the reduction of the thickness of smartphones or mobile phones. Here, a problem occurs with the integration of the camera module and the camera modules, respectively: due to the physical laws of optics, for each given camera module having the lateral dimensions X (extended in x-direction) and Y (extended in y-direction) a lower limit results for the height of the entire camera module Z (extended in z-direction). This height Z determines the minimum thickness of the entire apparatus, for example when orienting the height Z along a thickness of the smartphone or mobile phone. In other words, the camera frequently determines the minimum thickness of the smartphone.
An option for reducing the installation height of cameras is the usage of multi-aperture cameras including a plurality of juxtaposed imaging channels. Here, superresolution methods are used, whereby the installation height can be halved. Basically, two principles are known based, on the one hand, on optical channels each transmitting the entire field of view (Pelican Imaging, i.a. WO 2009151903 A3, TOMBO Japan) and, on the other hand, only imaging a partial area of the total field of view (DE102009049387 and based thereon application DE102013222780).
A multi-aperture device can include an image sensor having one image sensor area per channel. An optical channel of the multi-aperture device is configured to project a partial area of the object area on a respective image sensor area and for this, the same comprises an optical element or an imaging optics, such as a lens, a portion of a decentered lens or a freeform surface having an optical center.
Further, with a single camera module and hence a single optical channel, it is not possible to obtain in depth information on the object area detected thereby. For this, at least two camera modules are necessitated, wherein the depth resolution can be maximized with increasing distance of the camera modules with respect to one another. The minimum installation height Z may possibly be reduced when multi-aperture cameras with superresolution and a linear arrangement of the channels are used (see again DE102009049387 and based thereon application DE102013222780). Here, however, the miniaturization depends on a superresolution factor usually not exceeding 2.
The integration of several camera modules necessitates additional space which is limited, for example when incorporating the camera module in the rear side facing the user for detecting an object area, which is, for example, facing the rear side in many common smartphones already by the additional integration of a screen in the same side of the housing.
Further, it is basically possible to reduce the installation height Z of the individual camera optics by reducing the focal length f of the individual camera optics. However, it is well known to the person skilled in the art that this approach only results in a reduction of the imaging quality as regards to resolution and/or image noise when reducing the pixel size or reducing the number of pixels.